Are you sure is the cam bearing ? I would say connecting rod bearing. Cam bearing don't wear as fast because the cam turn 2 time slower than the crank. If you don't have knocking problem before, i would check crank mesurement and if good i would put new connecting rod bearing. What is the milage on that motor ?
400,429 and the 460 share the same bellhousing pattern than the 351m.
The block would probably be junk if that happened. What makes you think that ? A 400 is a direct replacement. A 429-460 will bolt to your c6 but there will be things to deal with. Motor mounts, exhaust, radiator, power steering & alt brackets, etc.
I done a cost on a rebuilt about 900.00 I can buy a new reman for 1200.00 with a 3 year warrentie. the motor and tranny will be the only part of my truck that I will not have worked on my self. I have never rebuilt a motor, I belive I could do it but hate to spend the money only to have it not run right.
cam bearing can be change with a special tool but the motor have to be remove. probably need a complete rebuild. Good time to raise the compression and install a bigger cam to make the real horspower and torque the 400 is capable. Look for a 400 crank, pistons have to be change anyway and the connecting are the same. so give a call or go to www.Tmeyerinc. He have anything you'll need.